FITNESS ABCs

BODY COMPOSITION

Obesity is defined as that percentage of body fat that begins to increase the chances for cardiovascular
disease. Ideal body fat levels for men are 12% to 17% and 18% to 22% for women. As previously
mentioned, body fat is essential for certain bodily functions. Sometimes body type, determined genetically,
prevents an individual from achieving unrealistic body shaping goals. There are basically three body types.
The Endomorph is characterized by a large block shaped body. The Mesomorph is characterized by a
solid muscular structure. The Ectomorph is characterized by a frail, slight build and very little fat.

Body Mass Index (BMI) is an accepted indicator. Originally used by insurance companies as a measure of
fitness. It is a ratio of weight to height. However, this method is not accurate for athletic builds. It is difficult
to explain to a client why they are considered obese by this method when their body fat level is only 5%.
For this reason, we won't include a BMI chart here. However, to calculate your BMI, use the following
formula for a 150 lb (68 kg) individual who is 65 inches (165 cm) tall:

BMI (English) = (Weight x 704) / (Height x Height) = 25

BMI (Metric) = (Weight x 10000) / (Height x Height) = 25

Underweight BMI less than 18.5

Healthy weight BMI 18.5 to 24.9

Overweight BMI 25 to 29.9

Obese BMI 30 to 39.9

These BMI interpretations are based On Clinical Guidelines on the Identification, Evaluation, and
Treatment Of Overweight and Obesity in Adults. NHLBI Obesity Education Initiative, National Institutes of
Health, 1998.

There are various other methods for determining the amount of body fat, none are exact. The most
accurate is hydrostatic weighing. The individual is weighed in air then weighed in water. The water weight
is subtracted from the air weight. The body fat percentage is derived from these two figures. There are
electrical impedance, ultrasound and infrared measuring devices also; both are not as accurate. The most
common and relatively accurate method is by skin caliper.

There are three methods of interpreting skinfold measurements to body composition. The first is the
Durnan Formula based on the four-point method and is based on a standard adult population. The second
is the Jackson-Pollack three-point method and is based on a lean athlete. The third is the Slaughter-
Lohman two-point method based on a child population of 8 to 18 years of age.